This invention relates to reinforced plastic materials and manufacturing processes.
A wide variety of products are produced utilizing thermosetting plastic polymer systems and fibrous reinforcement materials. It is frequently desirable to produce such products utilizing mat, fabric, or roving reinforcement in various combinations of two or more reinforcement layers. It is difficult, however, to produce such products without undesirable wrinkles and laps, and conventional production processes are therefore often laborious and wasteful.
For instance, prior pultrusion processing typically requires a number of glass fiber forms to be continuously unwound and subsequently combined with a polyester nonwoven fabric that becomes (together with plastic resin) the surface of the pultruded profile. These individual plys must progress through former shoes and then be submerged in a thermosetting polymer. The polymer-saturated materials are thereafter further formed by stripping shoes. Finally, the treated materials are pulled through a heated die where they are thermoset into profiles such as angles, rods, tubes, channels or sheets. Successfully handling the individual plys during this production process can be very difficult.
Reinforcement fabrics and mats have previously been bonded into reinforcement composites with polyester resins to facilitate pattern cutting and subsequent handling in thermoset processing. However, such polyester resins are expensive and require high temperature processing, which precludes use of such resins for bonding certain desirable reinforcement fabrics, mats and other materials.